Heat exchanger for fireplaces

ABSTRACT

A heat exchanger for an existing fireplace which includes a grate means and air-transporting means in communication with the grate means. The exchanger further includes a blower whereby when the air within the grate means is heated, the blower will move the heated air either outwardly into the room where the fireplace is located or alternatively blow it to another section of the structure. Alternatively, the structure could include within one section of the air-transporting means a supplemental heating means whereby the heat exchanger is useable for heating purposes even in the absence of a fire within the fireplace.

United States Patent 3,635,211 [4 1 Jan. 18, 1972 Englert [54] HEATEXCHANGER FOR FIREPLACES [72] Inventor: Henry 0. Englert, 510 lF" St.,Blaine,

Wash. 98230 [22] Filed: Apr.7,1970

[21] App1.No.: 26,245

[52] U.S.C1 ..126/ll2l [51] 1nt.Cl [58] FieldofSearch ..l26/120,l21

[56] References Cited UNITED STATES PATENTS 1,030,002 6/1912 Livingston..126/l21UX 1,468,964 9/1923 Groth ..l26/l21 2,015,485 9/1935Lindberg... .126/121 X 1,365,912 1/1921 Greene ..126/l21 Rutland..126/l2l Leibst ..l26/l2l Primary Examiner-Charles J MyhreAttorneySeed, Berry & Dowrey [57] ABSTRACT 3 Claims, 4 Drawing FiguresPATENTED JAN 1 a 1272 INVENTOR.

T mm n a 0 N w i A Q QM R N E H Y Y B HEAT EXCHANGER FOR FIREPLACESBACKGROUND OF THE INVENTION Whereas an open fire within a fireplace maybe extremely warming to the soul and atmospheric within the room, it iswell known that the heating efiiciency of such a device is extremelylow. There have been many attempts to capitalize upon the intense heatgenerated within the fireplace containing an open fire through the useof a metal lining within the fireplace surrounded by an area of air anda blower means to remove the heated air from behind the metal lining andforce it into the room. This has proven to be satisfactory but is notadaptable to those fireplaces which were built before the metal liningconcept.

It is an object of the present invention to provide a heat exchanger foruse within existing fireplaces which will not alter the fireplacestructure and yet will greatly increase the heating efficiency of thefireplace.

With this object in mind and as a feature of the present invention,there is provided a fireplace grate including hollow portions into whichair from the room may be drawn and expressed outwardly into the room ina heated condition.

It is another object of the present invention to provide a heatexchanger for use in existing fireplaces wherein the exchanger has theadded benefit of providing a means for retarding the rate of burn of thefuel.

In accordance with this object and as a feature of the presentinvention, there is provided a heat exchanger for use in an existingfireplace wherein the heated air is moved upwardly within the fireplaceand then transported forwardly within the firebox over the fuel to beexpressed into the room, and the means which extends over the burningfuel has as an integral part thereof, a plurality of fins which may beused as dampeners to slow the rate of the combustion.

Yet another object of the present invention is to provide a heatexchanger for use within existing fireplaces wherein the heat exchangermay be used as a source of heat even when there is no fire within thefirebox.

In accordance with this object and as a feature of the presentinvention, there is provided a heat exchanger for use in existingfireplaces further incorporating within the airtransporting meansseparate and independent heating elements which may be used for heatwithout the need for forcing the artificially heated air out into theroom.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an isometric view of afireplace having the inventive heat exchanger positioned therein;

FIG. 2 is a sectional view along lines 2-2 of FIG. 1 showing a generalconfiguration of the preferred embodiment of the inventive heatexchanger;

FIG. 3 is a front elevation of the preferred embodiment of,

the heat exchanger showing in detail the fire-dampening fins; and

FIG. 4 is an enlarged view of one of the fins of the heat exchangershowing how a secondary heating element can be used therein.

DETAILED DESCRIPTION OF THE DRAWINGS As can be seen in FIG. 1, there isshown a fireplace generally denoted as 2 having a standard firebox 4wherein a combustible fuel would be burned providing atmosphere and heatto the room. Resting within the fireplace there is a heat exchanger 6which comprises a base or grate means 8, an upstanding back portion 10,and a plurality of forwardly extending fins 12.

Referring now to FIGS. 2 and 3, wherein the basic structural elementsmay be more easily distinguished, it can be seen that the preferredembodiment comprises a pair of metallic beams 14 each adapted to supportone end of the heat exchanger device. Mounted upon the top of the beam14 is a screen 16 adapted to keep the heated coals up around theair-transporting pipes 18 which are mounted above the screen and extendbackwardly into the fireplace. The fuel supporting and airtransportingpipes 18 have an open forward end 20. Extending upwardly from the backof the beams 14 is a metallic plate 22 which is held in verticalposition by a pair of triangularly shaped sideplates 24 which extendfrom the front of the heat exchanger apparatus upwardly and backwardlyas best seen in FIG. 2. Each of the structural elements being made ofsheet metal have reinforcing bends upon their forwardly projectingsurfaces as seen in FIG. 3. These reinforcing portions also present asmooth, safe edge to those placing fuel in the fireplace.

The rearward ends of the heat-transporting pipes 18 bend perpendicularlyupwardly generally parallel to the plate 22 and form a verticalheat-transporting pipe 25 which again bends perpendicularly and extendsforwardly as best seen in FIG. 2.

Mounted upon the forwardly extending upper portion 26 of theheat-transporting pipe is a plurality of rotatable mounted elongatedfins 12 having a generally triangular shape as best seen in FIG. 4. Thefins 12 serve to both transport the heated air forwardly into the roomas depicted] by the arrows in FIG. 2 and likewise serve as a dampenermeans whereby the combustion within the firebox may be regulated. Themeans whereby the heat exchanger fins 12 may be used as dampeningdevices is most clearly shown in FIG. 3 wherein the dotted portions showhow the triangular-shaped fins are designed such that when rotatedtowards each other they will close off the portion of the updraft to thechimney, thus limiting the rate of combustion.

The heat exchanger will operate by means of natural convection once afire is in a state of combustion upon the lower heat-transporting pipes18. The air coming in through the open end 20 is heated and willautomatically rise through the section 25 and having no place else to gowill be expelled forwardly, as shown by the arrows in FIG. 2, outthrough the forward open portion 13 of the fins 12. However, it has beenfound that the entire heating system may be operated more efficientlywith the assistance of an additional blower means. As seen in FIG. 2,mounted distally from the heat exchanger, there will be a motor M, anappropriate blower 30 and an equalization chamber 32 leading to a.transverse connecting pipe 33 assuring that the same approximate airmovement will reach all of the air-transporting tubes.

With the addition of the supplemental blower described above, the heatexchanger is more efficient for transporting heated air into the roomadjacent the fireplace. The output of the blower is expressed into eachof the upright tubes 24 by means by a single upright tube 34 from theblower means ex tending into the interior of the upright tube 25 thuscausing, when in operation, a definite vacuum condition within theforward or lower portion of the heat exchanger mechanism. The use of theauxiliary blower means likewise permits the heated air to be transportedto other portions of the house by means of an auxiliary air transporttube 36 which is tapped into the upper portion of one or more of theheat exchange transporting tubes.

Referring now particularly to FIG. 4, there is shown a heating finidentical to that depicted in FIGS. 2 and 3 with the exception thatmounted within the heat exchanger fin which is hollow is an electricalheating element 40. The mounting of the heating element 40 within thefin 12 allows the blower to be run and the heat exchanger unit to beused for heating the room adjacent the fireplace even where there is nofire within the firebox.

The supplemental heating element is shown as electrical but is notlimited thereto and may be operatively connected by any means well knownin the art.

Thus, it can be seen that with the use of applicant's inventive device,the efficiency of a presently existing fireplace may be increasedthrough the use of either natural convection or alternatively auxiliaryforced air. Further, it can be seen that applicants device may be usedfor supplementing the heat within a room even without the need for afire within the firebox.

It is understood, of course, that the applicant's device is not limitedto use with a wood fire within the firebox, but could equally well beused with a gas fire or charcoal since the main purpose of the heatexchanger is to pass heat into the room and each of these fuels willprovide sufficient heat to serve this function.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. A heat exhanger for placement in the firebox of an existing fireplaceand increasing the heat output thereof comprismg;

a base portion for supporting the burning material and including aplurality of generally parallel hollow tube sections open at one end andadapted to be placed generally parallel to the floor of the firebox withthe open ends extending toward the front,

a back portion comprising a plurality of hollow tubes in gaseouscommunication with the tubes in the base portion and adapted to carrythe air heated in the base portion upwardly by convection, a top portionincluding a plurality of elongated hollow elements in gaseouscommunication with the tubes of the back portion, said hollow elementspivotable about a substantially horizontal axis and adapted tosubstantially close the top of the heat exchanger when in a closedposition and allow free flow of the combustion gas when open wherebyconvection will force heated air upwardly through the tubes and out intothe room and if it is desired to suppress the fire, the top elements maybe pivoted to slow the draught.

2. A heat exchanger as in claim 1 wherein the top elements are of asubstantially isosceles triangularcross section having a narrow baseallowing relatively unrestricted airflow when the top elements are inthe open position.

3. A heat exchanger as in claim 1 wherein the top elements enclose anauxiliary heat source whereby the heat exchanger may be used to heat theroom when the fire is not ignited.

* l IF

1. A heat exhanger for placement in the firebox of an existing fireplaceand increasing the heat output thereof comprising; a base portion forsupporting the burning material and including a plurality of generallyparallel hollow tube sections open at one end and adapted to be placedgenerally parallel to the floor of the firebox with the open endsextending toward the front, a back portion comprising a plurality ofhollow tubes in gaseous communication with the tubes in the base portionand adapted to carry the air heated in the base portion upwardly byconvection, a top portion including a plurality of elongated hollowelements in gaseous communication with the tubes of the back portion,said hollow elements pivotable about a substantially horizontal axis andadapted to substantially close the top of the heat exchanger when in aclosed position and allow free flow of the combustion gas when openwhereby convection will force heated air upwardly through the tubes andout into the room and if it is desired to suppress the fire, the topelements may be pivoted to slow the draught.
 2. A heat exchanger as inclaim 1 wherein the top elements are of a substantially isoscelestriangular cross section having a narrow base allowing relativelyunrestricted airflow when the top elements are in the open position. 3.A heat exchanger as in claim 1 wherein the top elements enclose anauxiliary heat source whereby the heat exchanger may be used to heat theroom when the fire is not ignited.